This invention relates to processes for treatment of concentrated oxidant waste streams. The new method may combine a wastewater stream with an oxidant-laden stream to produce a blended stream that may be treated in a bioreactor.
Existing processes used to biologically treat concentrated oxidant streams may typically require a dedicated deoxygenating step, require long residence times due to high solution salinities, require the addition of an exogenous substrate such as ethanol, or require inoculation with exogenous salt tolerant bacteria. As an example, nitrate and perchlorate may be removed in a drinking water treatment process. If a brine line discharge may not exist or be permitted, the waste streams may often be treated using a dedicated brine bioreactor designed to degrade nitrate and perchlorate in a waste stream. There may be several problems associated with biologically treating saline waste streams. Microbial cultures may be very sensitive to slight changes in ionic strength, that is, total dissolved solids. Increased salinity may tend to disrupt normal metabolic function and thereby reduce degradation kinetics. Treating saline wastewaters can increase the concentration of effluent solids. Acclimating effective salt tolerant cultures using traditional microbial sources, for example, sludge from a municipal wastewater treatment plant, may be difficult.
Other considerations for dedicated brine bioreactors may be that the waste stream must be anoxic/anaerobic to achieve biological oxidant reduction. Also, an exogenous electron donor such as acetic acid or ethanol must be added to the system to serve as a substrate, an electron donor.